Touran courtesy light

New member so please bear with me. I was trying to get at the wiring behind the courtesy light and storage boxes. Thinks I've done something as the lights and courtesy lights aren't working now. I tried accessing the wiring and the lamps by taking out the 4 screws that attach the unit to the roof. With the bolts out I expected the unit to come away. It didn't.

Do I have to prise it out somehow? I'd appreciate some advice on how to get it down and gain access to the wiring.

Thanks Pavarotti.